In an operating device of a type in which a chemical solution is discharged from a nozzle by means of a pump, the chemical solution passes preliminarily through a filter apparatus before the chemical solution is discharged from the nozzle in order to prevent troubles such as clogging of the nozzle due to the foreign matters in the chemical solution or blur or stain on the printed matter, or in order to suppress the change in the discharge amount caused by the inclusion of air into the discharge nozzle of the chemical solution. Although not particularly shown in the figures since it is out of the scope of the present invention, the operating device described above includes a dispenser cleaning device used in a semiconductor manufacturing machine or an ink filtering machine used in a printer. FIGS. 9 and 10 are perspective views each showing a conventional filter apparatus 10. The filter apparatus 10 has a holder 12, and a generally cylindrical filter body 20 that is sandwiched between a front panel 16 and a rear panel 18, which extend upwardly from each of a front and rear side edge portions of a bottom panel 14 of the holder 12. The filter body 20 is provided with a fluid inlet 22, which projects forwardly from the center position of the filter body 20 and into which a chemical solution to be filtered is injected, and a fluid outlet 24, which projects forwardly like the fluid inlet 22 at the position apart from the fluid inlet 22 in the radial direction and from which the filtered chemical solution passing through the filter body is discharged.
The front panel 16 of the holder 12 is formed with a single vertical cutout 26 through which the fluid inlet 22 and the fluid outlet 24 of the filter body 20 can simultaneously be inserted from above in a longitudinal direction. The front panel 16 and the rear panel 18 are biased in the direction in which they are close to each other so as to hold the filter body 20 therebetween. Therefore, when the filter body 20 is inserted between the front panel 16 and the rear panel 18 with the fluid inlet 22 and the fluid outlet 24 inserted into the vertical cutout 26, the filter body 20 is held between the front and the rear panels, and the fluid inlet 22 and the fluid outlet 24 inserted into the vertical cutout 26 fixes the filter so as not to rotate.
The filter body 20 is used during the operation of filtering the chemical solution in such a manner that the fluid outlet 24 is positioned below the fluid inlet 22 as shown in FIG. 10. Air included in the chemical solution flowing from the fluid inlet 22 moves upward in the filter body 20 to be trapped.
In order to eliminate the trapped air from the filter body 20, it is necessary to perform a series of operations as mentioned below. The filter body 20 having the fluid inlet 22 and the fluid outlet 24, to which the tubes are attached, is lifted up so as to temporarily remove the filter body 20 from the holder 12. Then, the filter body 20 is inversely rotated by 180° so as to position the fluid outlet 24 above the fluid inlet 22, and then, the filter body 20 is again inserted into the holder 12 from above so as to attach the filter body 20 to the holder 12. With this state, the air releasing operation is performed for a predetermined time. After the air releasing operation, the filter body 20 is again lifted up so as to remove the filter body 20 from the holder 12. Thereafter, the filter body 12 is inversely rotated by 180° so as to position the fluid outlet 24 below the fluid inlet 22. Then, the filter body 20 is inserted into the holder 12 from above so as to attach the filter body 20 to the holder 12. Thus, the filter body 20 is returned to the used state shown in FIG. 10.
However, during the air releasing operation described above, a user has to secure a physical space, which is necessary and sufficient for accessing to the holder 12, and lifting up the filter body 20 so as to remove the filter body 20 from the holder 12, in a limited space of the device, to which the filter apparatus 10 is incorporated, without interfering with a chemical solution bottle or other filtering-related components that are housed in the limited space. This produces a limitation upon making the whole apparatus compact. The operation, in which the filter body 20 is removed in the narrow and small space with the tubes connected to the fluid outlet 24 and the fluid inlet 22 respectively and this filter body 20 is inversely rotated by 180° is a cause of deteriorating operability and workability related to the filter apparatus 10.